As you can see from the picture of the one I was sent, it looks like the "E" (if it is an E) is cut from an image of a handwritten score. It might be for piano, or another keyboard instrument, as the notes at the "bottom" of the E look like a right-hand and left-hand part respectively. Of course, it might not be and without the clefs, we can't even be sure what notes they are. I held the letter up to the light to see if anything was written on the piece of index card it's glued to, but there doesn't appear to be. The glue is sticky enough and paper thin enough, that I'm unsure if I can separate the two pieces without destroying them. On yours, I saw the words "Brevier Type" which seems to be an outmoded type size, similar to 8pt. font. Source. Then we've got that table, which reads "Time" and then what seems to be prices? Anything else you notice about yours?